DE1769054B2 - Contact adhesive based on styrene-butadiene copolymers - Google Patents

Description

to give good creep or shear strength for an adhesive. A use of emulsion polymerized Styrene-butadiene rubber has a very low reinforcement effect. It has, however pointed out that a material such as the random block copolymer, which in his Molecules having polystyrene domains associate with the polysyrene end blocks of the terminal block copolymer blends, is attracted by and / or bonds with them to achieve the desired adhesive strength without loss of creep or shear strength. A reinforcing effect will be by one copolymer with the other similar to that by filler in the binding molecules of the two copolymers achieved together.

The copolymers used in the contact adhesive according to the invention have precisely fixed melting points, and it can be assumed that the polystyrene regions or blocks are first in the copolymer molecules melt, since every molecule has such areas, which are probably between exert a binding effect on the two copolymers.

During the production of the contact adhesive according to the invention it was found that adhesion promoters such as for example resins which are at least partially compatible with both copolymers used in the mixture tolerate, significantly improve the desired properties of the finished adhesive. Apparently are these resins with the terminal and random copolymers soluble due to the amorphous properties of both copolymers. Straight lines are particularly suitable chained hydrocarbon resins. Certain abietic acid derivatives can also be used as adhesion promoters use, with polar resins appearing more suitable, albeit some essentially non-polar resins are useful. It is possible to add resins in a larger proportion by weight, in order to achieve the desired properties of the adhesive, in particular with regard to its adhesive strength achieve. In general, the adhesion promoters customary for rubber-like styrene-butadiene copolymers appear suitable for the contact adhesive according to the invention.

The adhesive mixtures according to the invention can be prepared by mixing the individual components and dissolving them in usual amounts of a suitable solvent as in usual amounts a suitable solvent such as Toiuo! -, cyclohexane, Ethylene chloride, 1,1,2,2-tetrachloride, Srombenzoi; Diethyl ether. Prepare hexane, toluene or methyl ethyl ketone and then in Apply in any desired way on a suitable carrier medium or a tape or dsl., whereupon they are then dried or the solvent is otherwise removed. Usually the copolymeric portions of the mixture are first mixed with one another in the solvent and then the adhesion promoter added in order to achieve a sufficient bond strength. Depending on the requirement the mixture may contain two or more resins. However, these resins are allowed to use the polystyrene areas do not interfere with the copolymer molecules.

Any desired amount of any other suitable ingredients can also be added to the mixture add, such as antioxidants. Antiozonants, ultraviolet light absorbers (UV absorbers), Plasticizers and fillers.

The contact adhesive according to the invention preferably contains:

Random block copolymer 70 parts by weight

Terminal Brock Copolymer 30 parts by weight

Hydrogenated pentaerythritol ester

Rosin 85 parts by weight

using suitable solvents as required such as ^; '° aliphatic hydrocarbons (hexane) or aromatic hydrocarbons (toluene) or their mixtures are added.

In the table above, the weight proportions of the individual components can be broken down into the following Change boundaries without affecting the desired adhesive strength:

Random block copolymer 90 to 50 parts by weight terminal block copolymer 10 to 50 parts by weight

Pentaerythritol ester of
hydrogenated rosin 50 to 150 parts by weight

In addition, the following can also be used, for example, in the above-mentioned mixture example Additives can be added either in their entirety or as required:

function Art proportion of
(phr) Preferably lphr - 2 phr Antioxidant Phenol or quinoline 0.5 to 2.5 only for special Antiozonant wax 0.5 to 2.5 Purposes UV absorber Substituted benzophenone 1 to 4 for special purposes only Plasticizers Monomeric esters or polyesters 1 to 25 Fillers Georgia Kaolin or Silica 0 to 100 Raffinate

phr = parts per hundred parts of rubber hydrocarbon.

The above substances are an antioxidant and 2 parts of a UV absorber, typical commercial substances, which in the 65 The proportion of plasticizers should be to achieve Adhesive mixtures according to the invention can be used - - -

are. The aforementioned special mixture of the contact adhesive according to the invention thus contains 1 part maximum creep resistance are not in the upper part of the application range, while to achieve maximum adhesion the higher weight proportions

the fillers should not be used =

Other resins which have found satisfactory in the above Gewichtsmengeu results are listed below, s these resins are soluble in the copolymers is at least partially without affecting the polystyrene portions of the molecules, and these resins individually in Jen indicated proportions or combined usable are:

Polyterpene,

Kumaron,

Abietic acid,

Vinyl toluene, Alpha methyl styrene,

natural fossil,

Terpene phenol,

Hydrocarbon,

Esters of rosin polymer.

Esters of hydroabietyl alcohol,

Ketone resin,

chlorinated polyphenyl.

To determine the best mixing ratio of the two elastomers in the contact adhesive according to the invention Experiments were carried out, with the

The proportion of the adhesion promoter was kept constant at 70 parts to 100 parts of rubber or elastomer. The test results are shown in the table below:

Table I.

A. B. example D. E. F. Random block copolymer content ...
to
Terminal-BlockcoDolvmer 90
10
4.5
(100% cch)
4.3
(100% coh)
6.5 80
20th
6.9
(100% coh)
6.7
(100% coh)
4.3 70
30th
6.4
(25% coh)
6.1
(15% coh)
4.3 65
35
4.9
5.0
4.3 60
40
4.7
4.4
3.8 50
50 30 minutes room temperature,
Peel Strength (lbs. Per inch) ...
Peel strength after 16 hours
Rest time (lbs per inch). .... 4.4
4.6 Adhesion (lbs. Per inch) 3.7

As an adhesion promoter, all mixtures contained 70 parts of pentaerythritol ester of hydrogenated rosin, while approximately 2 parts of an antioxidant was added.

The above tests show that the best bond strength can be achieved if the cohesion breaks off. The limit of breaking off 100% cohesion appears to be between 20 and 30 parts of Kraton-10 to lie.

To determine the most advantageous amount of adhesion promoter in the mixture according to the invention Further tests were carried out, and the preferred pentaerythritol ester proportion per 100 parts of elastomer seems to be between 75 and 100 parts, with better curing properties in the lower range of resin content were determined. For the adhesive selected for these tests broke adhesion before cohesion. These attempts different resin concentrations at constant The ratio of the two elastomers resulted in the following data:

Table II

A. B. C. D. E. Example
F. :1
G H I. 65 ^J I 65 65 65 65 65 65 65 65 35
90 65 35
50 35
55 35
60 35
65 35
70 35
75 35
80 35
85 4.6 35
85 4.6 4.3 4.5 4.6 4.2 4.3 4.3 4.4 5.1
3.6
2.16 4.5 4.4
4.5
2.02 4.9
3.2
2.10 5.1
3.8
2.01 4.3
3.9
2.15 4.3
2.5
2.04 4.8
2.3
2.12 4.9
2.4
2.00 5.1
2.6
2.04 5.0
3.5
2.16

Random block copolymer proportion ... too

Terminal block copolymer

Pentaerythritol ester (phr)

Peel strength after 30 minutes at room temperature (lbs. Per inch)

Peel strength after drying overnight at room temperature
(lbs. per inch)

Adhesion (lbs. Per inch)

Layer weight

65

35
100

4.8

5.4
4.0
2.13

ses
Other
iuf
de.

Table III

Layer weight (g / 100 in. ² )

Peel strength according to

30 minutes at room temperature (lbs./in.) ....

Adhesion (ibs./in.) ..

Peel strength after drying overnight at room temperature (lbs./in.)

Creep Resistance (2 lbs. Static shear load at 90 ⁰ F)

Creep resistance (10 lbs. Static shear load at room temperature)

2.0

4.1 4.7

4.1

40 hrs. 9 min.

2.18

unlimited 842 hours

The test mixtures contained 2 parts by weight of an antioxidant per 100 parts of elastomer.

The aforementioned experiments are in the relevant

Industry common and have been among equals

Conditions carried out to ensure perfect

to be able to carry out corpse. The cohesion gap

fracture during the peel strength tests became visible estimated.

While in the above description detailed tests of very specific compositions are shown it is still possible, according to the desired properties of the end product, to modify the Quantities vary. The specified amounts of the various ingredients can thus be found in the most cases vary by a few percent without that

ίο this significantly affects the quality of the adhesive would.

Especially with regard to high creep resistance in connection with perfect adhesion and good peel strength should be the inventive

is glue known to be superior to what can be seen in the adjacent table.

The above-described copolymers have proven themselves in practice for the contact adhesive according to the invention excellent proven. Others solution polymerized

ao styrene-butadiene copolymers with similar physical Properties and polystyrene blocks that fit each other or polystyrene blocks in another Attract molecules or copolymers to form polystyrene areas, which, however, are about

as 5 to 50 parts by weight of styrene and about 90 to 50 parts by weight Containing butadiene can also be used to produce the contact adhesive according to the invention use.

Claims (3)

final adhesive mix unchanged. The claims: Resins are mixed with the styrene-butadieri copolymers and are at least partially in them 1. K. contact adhesive containing a soluble. rubbery styrene-butadiene copolymers 5 These copolymers have polystyrene terminals with Polystyrene blocks at the molecule ends and or random blocks, These polystyrene blocks pull an adhesion-promoting resin, ge ke η η ze i eh- each other and consequently form block areas net by a mixture of 50 to 90 Ge in the adhesive mixture. A preferred weight sharing a rubbery styrene / buta ratio between the random, terminal diene copolymers with polystyrene random blocks io and resin components is in parts by weight in the molecules, added to 100 parts by weight 70:30:85. by a rubber-like styrene-butadiene-Co- By mixing certain weight percentages polymer with polystyrene blocks on the molecule of solution-polymerized rubber-like ter- end, the copolymers no more than the minal-styrene-butadiene block copolymers with solution Half of the parts by weight of residual styrene monomer depolymerized rubber-like random styrene but hold, and from 50 to 150 parts by weight of a tadiene block copolymer together with compatible adhesion-promoting resin, which can be combined with the co-adhesion promoters such as resins, polymer compatible. and if necessary, as could be determined, a contact adhesive usual additives. with excellent properties. as 2. Contact adhesive according to claim 1, characterized in that a commercially available poly has been identified as particularly suitable, that syndiotactic copolymers proved styrene terminal block copolymer, which in be used. Parts by weight 51.75% trans-1,4: 9.97% vinyl-1,2 3. Contact adhesive according to one of claims 1 and contains 38.2% cis-1.4 fractions. At one of the and 2, characterized in that rectilinear elastomer is a copolymer, Chained hydrocarbon resins are used, which according to the method of the USA patent the. 3 231 635 is manufactured. The butadiene-styrene-co- polymer can be about 5 to 15% vinyl, 30 to 60% have cis and 30 to 60% trans bonds. As is described in the aforementioned patent, 30 can this copolymer of an isoprene-styrene Contact adhesives are produced in a wide variety of copolymers. That for the invention Settlements are known and are increasingly used in adhesive blends, such as copolymer Dimensions used for a wide variety of purposes. The described in the patent, from an alkenyl- previously known contact adhesives, however, can be produced in aromatic hydrocarbons, preferably with regard to very high creep resistance with one or more monovinyl-substituted at the same time high adhesive strength and high peel strength even aromatic hydrocarbons such as styrene, «-Me- much to be desired, so that the task arises, thyl-styrene, vinyltoluene, vinylxylene, vinylnaphthalene to create a contact adhesive, which can be penetrated, etc. The material with which a member of the particularly high creep strength with a high level of said group is block copolymerized is a Excellent adhesive strength, extremely resistant 40 conjugated diene hydrocarbon with preferred * - against peeling and also a large storage of 4 to 8 carbon atoms per molecule and ability. forms one or more butadiene, isoprene, penta- The subject of the invention is a contact adhesive with diene-1,3-, 2,3-dimethyl-butadiene series and the like.
a content of a rubber-like styrene-butadiene-Db adhesive mixture contains larger amounts of copolymers with polystyrene blocks on the molecule 45 of a random styrene-butadiene block copolymer, wells and an adhesion-promoting resin, characterized by solution polymerization, a piner mixture is characterized by a mixture of 50 to 90 parts by weight, for example, about 76.5 parts of butadiene and about parts of a rubber-like styrene-butadiene copoly- 23.5 parts styrene is formed and has polystyrene areas with random polystyrene blocks in the moles. A commercially available product has proven to be suitable for such a copolymer, supplemented to 100 parts by weight with a chewing material, for the adhesive styrene-butadiene copolymer according to the invention with a poly-substance mixture, styrene blocks at the ends of the molecule, with the code Random blocks of polystyrene and in weight polymers no more than half the weight parts make up about 57.1% Trans-1; Contains 9.38% vinyl-1,2 and residual styrene monomer, and from 50 to 150 Ge contains 33.55 cis-1.4 parts. By means of spectrographic weight parts of an adhesion-promoting resin, which was carried out by X-ray analysis, it was found that both are compatible with the copolymers and that the given copolymers are syndiotactic. That if usual additions. Copolymer is made according to the teaching of the USA. In particular, 3 251905 are manufactured for the contact adhesive. Mixtures of solution-polymerized rubber-like copolymers used for the invention-styrene-butadiene copolymers used with no more than 60 according to the manufacture of a contact adhesive 50 parts of styrene, which will have polystyrene regions, is preferably styrene in 50 units at most. Such a mixture may be from one part by weight to 50 parts by weight or more syndiotactic terminal block copolymer and one of the copolymer material are present as larger Syndiotactic random block copolymer with polystyrene components makes the copolymer too brittle and / or too There are styrene blocks in the molecules. Purpose 65 i.art. The proportion of dea in the invention is moderately If the filler contained in an adhesive the terminal block contact adhesive is only used copolymer alone, only one results so erupted that it has the physical properties of poor adhesiveness, however, it seems that this is the case